Overview
1-Wire Device IDs
X1W-1 Inside Sensor/Interface Board
X1W-2 Outside Sensor/Interface Board
EMP (Lightning) Sensor
Temperature Sensors
Humidity Sensors
Barometric Pressure Sensor
Aspirator Control for Humidity Sensor
Rain Gauge Heater Control
Background Radiation Monitor
WR-SAME Receiver/Decoder
One of the strong features of the WXN software suite is the ability to support sensors and add-ons not supported by the weather station. This is largely due in part to the 1-Wire technology introduced by Dallas Semiconductor. This allows only using one serial port to support many additional sensors with no practical limitations as to the number. The only add-on that does not fall into this group is the WR-SAME receiver/decoder which requires it's own serial port.
Note! - If the server is running, and you make any configuration changes, you will have to restart for the change to take effect.
With the exception of the WR-SAME decoder, all configuration is found in wxnhostd.conf.
If you have any ideas about additional sensors or add-ons, contact me.
The following table lists the device IDs for the different types of 1-Wire devices used in the sensor and interface circuitry. These are the last two digits of the serial number which is listed to the screen with either the tstfind or the individual utilities that support each type.
To use tstfind or any of the other utilities, you must specify the serial port the 1-Wire serial adaptor is attached to. For example:
./tstfind /dev/ttyS1
In this example, COM2 is used (COM1 is ttyS0). Note that the leading ./ is required to execute the utility.
Digits Device Type Utility 10 Temperature (DS18S20) temp 26 A/D (DS2438) gethumd 05 PIO (DS2405) swtsngl 1D Counter (DS2423) counter
X1W-1 Inside Sensor/Interface Kit
The X1W-1 is an indoor sensor/interface kit that was designed to work with either this server code or the TAPR T-238/T-238+. The kit offers the following sensors and interfaces:
- Indoor Temperature Sensor
- Barometric Pressure Sensor
- Rain Gauge Interface (can optionally be strapped for background radiation monitor)
- EMP (Lightning) Detector Interface
- Power Control for the X1W-2 Aspirator
- Power Control for a Rain Gauge Heater
- RS-232 serial interface for the 1-Wire Bus
- Provision for adding one iButton device
The rain gauge and EMP sensor interfaces employ opto-isolators to help isolate the external interfaces. The board also features a 1-Wire loop-thru as well as an optional strong pull-up to the +5V bus and external +5V supply on the 1-Wire interface.
The X1W-1 kit is available through TAPR. The manual can be viewed on-line at http://www.tapr.org/~n4xi/x1w-1/
Configuration - The configuration parameters that must be set in wxnhostd.conf are discussed below with each sensor.
X1W-2 Outside Sensor/Interface Kit
The X1W-2 is the outdoor complement to the X1W-1. This kit provides following features:
- Outdoor Temperature Sensor
- Humidity Sensor
- Aspirator (fan) for temperature/humidity sensors
- Rain Gauge Interface*
- EMP (Lightning) Detector Interface*
*Parts not supplied. Assumes purchaser also bought the X1W-1 and wishes to put the interfaces for these two components on the outside board. Otherwise, user must supply additional parts as required.
Note! - If you want an inside humidity sensor, then purchase or build the X1W-1 kit and use it indoors. The aspirator and temperature sensor need not be installed if using it only for an indoor humidity sensor. Configuration discussed below.
As with the X1W-1, the X1W-2 is a kit available through TAPR. The manual can be viewed on-line at http://www.tapr.org/~n4xi/x1w-2/
Configuration - The configuration parameters that must be set in wxnhostd.conf are discussed below with each sensor.
The X1W-4 EMP (lightning sensor) is in kit form from TAPR. The X1W-4 was designed to work with the interface provided in either the X1W-1 or X1W-2 kits. If you do not wish to purchase the X1W-4, compatible sensors can be purchased and/or built.
The interface expects a closed circuit with an Ron of approximately 100 ohms whenever a lightning discharge is detected. Although not required, the circuit should support a rise-time of 1 mS or less.
Here are several sources for the sensors:
- X1W-4 kit from TAPR (recommended)
- LSU-30 from Stormwise
- Bitson 1-Wire Lightning Detector (homebrew)*
- Radmore (N2PWP) Lightning Detector (homebrew)*
*These circuits will require modification so that they have an open-collector output.
Configuration - To enable the EMP sensor interface, in wxnhostd.conf uncomment the line with Emp = n and set the parameter to 'y':
Emp = y
Three different types of temperature sensors are supported by the host server. They are:
- Inside
- Outside
- Soil
All temperature sensors utilize the Dallas Semiconductor DS18S20 1-Wire sensor. The DS18S20 is accurate, reliable and draws it's power directly from the 1-Wire bus. The inside temperature sensor for the X1W-1 and outside temperature sensor for the X1W-2 use this device.
Configuration - If only one DS-18S20 sensor is used, you only need to enable the sensor in wxnhostd.conf. If you have more than one, you will need to run the tstfind 1-Wire utility and record the serial number for each sensor. This information must then be entered along with enabling the sensor into wxnhostd.conf. The example configurations following each type show both the enabling parameter and serial number entries.
Inside - If you have the X1W-1 Inside Sensor/Interface kit, the inside temperature sensor is included. Just be sure the correct jumper is set to enable the sensor. If you are making your own, you probably don't need to seal the sensor, but do be careful that the leads are adequately protected so that you won't have any shorts. Example configuration:
OwInsideTemp = y
If more than one temperature sensor is used, this line will also be required. The serial number shown is only an example. It must be replaced with the one for your unit.
OwInsideTempSN = 9C00080034D2FB10
Outside - If the outside sensor is used, the current temperature will be that of this sensor, not of the weather station sensor. It is very important that the leads are completely sealed so that no moisture can get into the connections. Use of heat shrink with glue, hot glue or coax seal can be used to seal the connections. As with any outdoor temperature sensor, an appropriate radiation shield should be used to prevent the readings from being skewed by solar radation. Example configuration:
OwOutsideTemp = y
Again, at the risk of being repetitive, if more than one temperature sensor is used, this line will also be required. The serial number shown is only an example. It must be replaced with the one for your unit.
OwOutsideTempSN = 3A0008003522A310
Soil - Soil temperature is measured usually at 6" and/or 8" depth(s). The server supports two soil temperature sensors. Details on how to build your own soil temperature sensors can be found at N4XI's web site. Example configuration:
OwSoilTemp = y
If more than one temp sensor is used anywhere in the system, this line will also be required. The serial number shown is only an example. It must be replaced with the one for your unit.
OwSoilTempSN = 300008004FDF7210
If a second sensor is used, the following also needs to be set. If two soil temperature sensors are used, the serial numbers must be specified.
OwSoil2Temp = y
OwSoil2TempSN = serial_number
The humidity sensor is part of the X1W-2 kit. If you wish to build your own, the schematic and calibration procedure can be found in the manual for the X1W-2.
Example configuration:
OwOutsideHumidity = y
If the barometric pressure sensor is used along with the humidity sensor, the following line will also be required. The serial number shown is only an example. It must be replaced with the one for your unit.
OwOutsideHumiditySN = 380000001A1C9926
If an indoor humidity sensor is used, The parameters that need to be set are:
OwInsideHumidity = y
OwInsideHumidtySN = serial_number
Note that if a 1-Wire indoor humidity sensor is used and one exists on the weather station, the one on the weather station will be ignored.
The barometric pressure sensor is part of the X1W-1 kit. If you wish to build your own, the schematic and calibration procedure can be found in the manual for the X1W-1.
Example configuration:
OwBarometer = y
If the outdoor humidity sensor is used along with the barometer, the following line will also be required. The serial number shown is only an example. It must be replaced with the one for your unit.
OwBarometerSN = 380000001A1C9926
The following parameter permits tweaking the barometer to adjust for changes in altitude without having to run the baromcal utility. The integer value can be positive or negative and is expressed as tenths of a milibar. It is added to the current pressure reading before it is stored. The default value is zero.
OwBarometerOffset = 0
Aspirator Control For Humidity Sensor
The aspirator control is part of the X1W-1 kit. It is used to turn the aspirator (fan) on in the X1W-2 kit when the humidity levels are at 80% or above. Use of the aspirator increases the accuracy of the humidity readings. Turning on the aspirator only when needed extends the bearing life of the fan. If you wish to build your own control interface, look at the manuals for the X1W-1 and X1W-2.
Example configurations:
OwAspiratorCtrl = y
If the rain gauge heater control is used along with this one, the following line will also be required. The serial number shown is only an example. It must be replaced with the one for your unit.
OwAspiratorCtrlSN = 750000002237E105
The default trip-point of 80% works well. However, it can be changed with with the following setting:
AspCtrlTrip = 80
The rain gauge heater control is part of the X1W-1 kit. It is used to turn a rain gauge heater on if the temperature falls below 35°. This permits detecting snow, ice, or mixed precipitation in the winter months. If you wish to build your own control interface, look at the manuals for the X1W-1 and X1W-2.
Example configuration:
OwHeaterCtrl = y
If the humidity aspirator control is used along with this one, the following line will also be required. The serial number shown is only an example. It must be replaced with the one for your unit.
OwHeaterCtrlSN = F6000000223B7F05
Since 9/11 there has been an increased interest in the ability to measure background radiation levels. Aware Electronics has a line of affordable background radiation monitors that are reliable, accurate and employ a readily usable interface. The matching interface is available in the X1W-1 kit. The X1W-1 supplies all necessary voltages and level translation.
Example configuration:
Rad = y
The radiation monitors require a Cesium 137 correction factor. The following table lists the correction factor for the three Aware Electronics units supported.
Model Correction
FactorRM60 1050 RM70 1490 RM80 3545
The default setting is for the RM60 model. The following parameter will need to be set if you are using the RM70 or RM80. The example shows the offset for the RM70. If you are using the RM60, there is no need to set this parameter.
Cesium137 = 1490
The code for this server is currently under development.